Curved speaker wall geometry

[LinuxGeek]

Hi guys,
i received way too much mdf, so new speakers will be born. This time i will try something dfferent. Multilayer curved speakers. Not very efficient, if you see how much wood gets destroyed, but i dont know where to store it at the moment, so Thats not a problem.
I have seen this wall geometry somewhere and will try it myself, but my question now is :
Should i use this geometry also in the bass reflex tube or should it be smooth and round ? Did someone already try this kind of bass tube ?
It will be a 46 layer thing when ready .

 

[LinuxGeek]

Hmm,
Really noone has any experience with his kind of wall geometry ?

 

[Bigun]

Curves I get, but all those internal bobbly bits ? I've never tried it but my first impression of this approach is a solution looking for a problem - I'm rather skeptical about the benefits when perhaps foam is a better option (look at cutaway drawings of PMC speakers for example).

 

[GM]

Not me, ports normally ideally need to be as efficient, friction free as practical, so round and smooth bore.

GM

 

[LinuxGeek]

Thanks for your answers.
Ive seen this kind of design here : Sammy
My goal was just to create curved speakers, but after seeing the pbn design, i thought about giving it a try.
The BR tube thought was because i hear the air move throught the tube in my old speakers. I thought, perhaps with the "egg" pattern there will be less port noise.

 

[LinuxGeek]

So GM, you think a smooth br tube could be better, because of less friction ?

 

[bungelow_ed]

The reason you here port noise, is because the port is to small a diameter for the volume of air. My guess is you don't hear the air at lower SPL.

 

[LinuxGeek]

The reason you here port noise, is because the port is to small a diameter for the volume of air. My guess is you don't hear the air at lower SPL.

Yes, its the diameter, but its impossible to use a greater diameter, without running into resonance problems. If i increase the diameter, the port gets way too long.
I hoped to disturb the aitflow with the egg pattern and perhaps the noise would be less then. If i loose low extension, its not worth, thn i will make the br tube smooth.

 

[bungelow_ed]

LOL! I can't count the hours I've spent trying to cheat the laws of physics when it comes to port air speed. You've probably already thought of this, are both the port ends flared?

 

[LinuxGeek]

LOL! I can't count the hours I've spent trying to cheat the laws of physics when it comes to port air speed. You've probably already thought of this, are both the port ends flared?

Yes, they are. Both. Still way too much and too fast air .

 

[scottjoplin]

Put the port in the rear of the cabinet

 

[LinuxGeek]

Put the port in the rear of the cabinet

I already tried this and last time it did not help. Either i did something wrong or it does not really help to eliminate the air noise.
I have to say, that putting the br tube to the back does not help to increase spl, because there is no wall behind it. My speakers stand in the middle of the room. No gain because of walls or corners

 

[SaSi]

For the port noise, perhaps you need to explore the passive radiator options.
Regarding the layered mdf enclosure construction, it looks like a brute force approach to minimize resonances by adding mass but in most cases a constrained layer panel and/or heavy bracing gives equivalent results with less weight. And at 310lb (the example linked to) may look impressive on paper, until you need to lift and move it.